Compressor



'Patented Nov. 20, 1928. I

teme@ iJNlTED STATES PATENT OFFICE.l

CHARLES F. OSGOOD, OF CLAREMONT, NEW HAMPSHIRE, .ASSIGNOR T0 SULLIVAN MACHINERY COMPANY, A CORPORATION 0F MASSACHUSETTS.'

COMPRESSOR.

Application filed April 9, 1927. Serial No.'182,449.

This invention pertains to iiuid compresi sors, and more particularly to controlling mechanisms for compressors of the gasoline engine driven type. l

' An object of this invention is to provide an improved compressor controlling mechanism. Another object is to provide an improved controlling mechanism for a gasoline. driven compressor whereby the latter-may be automatically unloaded when the driving engine is initially started, the improved controlling mechanism being associated with the usual constant speed governor for the engine. Another object is to provide an improved compressor unloading mechanism associated with the constant speed governor for vthe compressor driving engine and having combined unloading operated by the variations in receiver pressure. A more specific object of this invention is to provide improved automatic controlling mechanism for a gasoline driven compressor whereby the speed of the engine automatically controls the engine throttle and the loading and unloading of the compressor, this controlling mechanism furth'er comprising receiver pressure controlled unloading mechanism for the compressor.v

Still another object is to provide an improved automatic unloading mechanism for a gasoline driven compressor whereby the Iengine may be started up. under no load and the'compressor may be automatically loaded when the engine comes up to speed. Yet another object is to provide an improved compressor controlling mechanism of an exceedingly simple and inexpensive character which may be applied to a standard compressor with a minimum of change. These and other objects and advantages of'this invention Will, however, hereinafter more fully appear. In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practice.

In this drawing,- I Fig. 1 is a side elevational view of a-gasoline driven compressor of the portabletype view illustratingif the speed increases, the 'rod 6 is shoved cto the right and if the speed decreases, the rod- 6 is drawn to the left. Through the above mentioned slot extends a connection 7, actherewith automatic means for controlling tuated from the rod 6, for controlling the supply of combustible gases to the motor. Secured to the end of the extension 5 is a cas- -ing 8 within which is disposed a valve 9 of the spool type. A stem 10 extending from the valve 9 is held in abutting relation with the end of rod 6 by a suitable spring 26 disposed in the opposite end of the valve casing. The annular groove 11 of the spool valve is shown in Fig. 2 as connecting a vent 20 with a port 12 in the valve casing.'v One end of the spool" valve is shown ascovering a port 13. The valve casing at the end opposite the cyl-v lindrical extension 5 is provided with a vent 14. A pressure fluid line lextend's between the port 12 and mechanism for unloading the Vpiston-like membery slidable in a, cylinder 23 which receives pressure Huid from the line 15. The piston-like member carries lingers 22 which are adapted to engage the inlet valve 24 of the valve mechanism 25 for the compressor cylinder. When the -ing'ers 22 env gage the'inlet valve 24 and force it 0E its seat,

the compressor runs unloaded.

- Between the port 13 and the airreceiver 19 extends a line 17. Between the lines 15 and 17 extends a bypass 18 which is controlled by a conventional pop valve 21. Such a pop yalve is adapted to be unseated when the pressure inline-.17 exceeds a predetermined/ amount, and to be returned to 'seating posi tion again when the pressure falls somewhat below that amount.

Before describing the operation, a review should be had of the diihculties which have been overcome. A gasoline motor has poor eficiency in starting and therefore should not be required to start up under a heavy load. I have s0 designed my improved unloading mechanism that-the compressor is always unloaded when the motor is not running and is not loaded until the motor has attainedits running speed. Furthermore, to obtain the best efiiciency, the delivery of air to the receiver should cease when the maximum pressure which the receiver is designed to take has been reached. I have provided anarrangement for unloading the compressor vwhen such a pressure is reached in the receiver.

Coming now to the operation of the mechanism, suppose that the operator has shut of the motor. As it comes to a-stop, the rod 6 is moved to the left, thereby allowing the spool valve 9 to assume such a position that the vent 20 is closed and the lines 17 and 15 are placed in communication by wa of the annular groove 11. Pressure fluid therefore passes from the receiver through lines 17 and 15 and actuates the unloading mechanisms 16. Since the preceding takes place whenever the motor is stopped, the compressor is always unloaded when starting up. p

rIhe operation of the device during starting of the compressor is easily understood. The governor 4 responds to the increasing speed ofthe motor 2 and gradually moves the rod 6 to the right. The spool valve 9 approaches the position shown in Fig. 2. The position of vent 20 has been so selected that it is not uncovered until the motor has reached its running speed. When vent 20 is uncovered, it is obvious from Fig. 2 that port 13 is closed; the groove 11 is therefore in communication with vent 20 and line 15 only; and the unloading mechanisms 16 are vented to the atmosphere. This allows the valves 24: to resume their function of controlling the inlets to the compressor, and the compressor is therefore loaded.

In conjunction with the unloading mechanism just described there has been provided the bypass 18' controlled by the pop valve 21. Should the pressure in receiver 19 pass a pref determined pressure (which should not be higher than the rated capacity of said receiver) the pop valve 21 will allow pressure Huid topass from line 17 through thel bypass 18 to line 15 and the unloaded mechanisms 16 are actuated. When the pressure in receiver 19 has fallen somewhat below the popoif pressure, the valve 21 is again seated. During this period of unloading there has been a leakage through the vent 20, but this is so small as not to affect the operation of the unloading mechanisms 16. When the pop valve 21 reseats,

Lacasse compressor is again loaded. The pop valve automatically takes care of variations in receiver pressure, whereas the valve 9 insures that the compressor beunloaded whenever the motoris started up.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent is p 1. In a compressor controlling mechanism, a driving engine having a throttle, a governor for said' throttle controlled by the speed of said engine, a fluid compressor driven by said engine,an unloading device for said compressor, acontrol for said unloading device operated by said cngine throttle governor, and a second control for said unloading device responsive to the compressor dischargepressure, said second mentioned control being independent of the engine throttle governor.

V2. Ina compressor controlling mechanism, a driving engine having a throttle, a governor for said throttle controlled by the speed 'of said engine, a fluid compressor driven by said engine, a pressure uid operated unloadin device for said compressor, a control for said unloading device operated by said engine throttle governor and a secondcontrol for said unloading device responsive to the compresser discharge pressure, both ofpsaid convtrols cooperating with a common iiuid passage leading to the unloadingdevice.

3. In a. compressor controlling mechanism, a driving engine having a throttle, a governor for said throttle controlled by the speed of said engine, afiuid compressor driven by said engine, an unloading device for said compressor, mechanism controlled by said speed con-4 trolled throttle governor fory automatically operating said unloading device to unloadsaid compressor when the engine is stopped and for automatically loading said compressor when the engine comes up to speed, said mechanism including means for alternativel admitting pressure fiuid to said unloading evice and for venting the latter to atmospheraiand mechanismresponsive to the compressor discharge pressure for operating said unloading device to unload said compressor when said discharge pressure reaches a predetermined maximum, said vent means Vbeing common to both said speed controlled unloading mechanism and said compressor discharge pressure controlled unloading mechanism. Y

4. In a compressor controlling mechanism, a driving engine, a compressor driven Vthereby, a constant speed governor for said engine, an unloading device for said compressor,

loo

Y actuated means for unloading said com- Y anism for the compressor including a valve controlled by the constant speed governor, a passage controlled by said valve, a source of pressurefluid'being connected lto one end of said passage, and a servo motor" for the unloading mechanism atv the other end.

6. In combination, a prime mover, a constant speed governor therefor, a compressor driven by said prime mover, pressure fluid pressor, and a spool'valve for controlling flow-of fluid to said unloading means, said spool valve being reciprocated under control of said governor. 1 Y

7. In combination, a prime mover, a constant speed governor therefor, a compressor driven by said prime mover, a receiver, unloading means for said compressor including a servo 'motor for actuating the unloading mechanism, means providing 'a passage for conducting pressure fluid fromsaid receiver to said servo motor, and a pair of valves controlling the flow of'ui'd through said passage, one of said valves beinga actuated by said governor and the other lbeing responsive to fluid pressure inlsaid receiver;

8. In combination a prime mover, controlling means therefor including .a throttle and a constant speed governor for regulating said throttle, a compressor driven by said prime mover, and unloading mechanism for said compressor having a pair of controls one ofA said controls being actuated 'by said prime mover controlling means and theA other ofl said controls being actuated in response to compressor discharge pressure independently of said prime mover cont-rolling means.

9. In combination, a prime mover, controlling means therefor including a throttle and a constant speed governor for regulating said throttle, a compressor driven by said prime mover, unloading mechanism for said compressor including a 'servomotor, and a pair of controls for the medium supplied to said servo-motor for actuating the same, one of said controls being actuated by said prime mover controlling means and the other of said controls being actuated in response to compressor discharge pressure independently of said prime mover controlling means.

. l0. In combination, a prime mover, a con- Y stautv speed governor therefor, a compressor f driven by said prime mover, and unloading mechanism for said compressor including -a servo-motor for actuating the same and means 'controlled by said constant speed governor in g device forsaid compressor, and mechanism controlled by said constant speed governor for admitting air Afrom said receiver to Vsaid unloading device to effect unloading of said compressor until said prime mover comes Jup to speed.

In testimony whereof I aiix my signature. CHARLES r. oseoon.. 

